1. Field of the Invention
The present invention relates to a semiconductor device having a good-quality film obtained by conducting a plasma treatment to an insulating film or a semiconductor film to improve the quality of the surface, in a case that a conductive film, the insulating film, the semiconductor film and/or the like are/is stacked, and a manufacturing method thereof.
2. Description of the Related Art
In recent years, a technique for forming a thin film transistor (TFT) having a semiconductor thin film (the thickness of several nm to several hundreds nm) formed over a substrate having an insulating surface such as glass has been attracted. Such thin film transistors have been widely applied to semiconductor devices such as ICs or electro optical devices, and further, such thin film transistors have been needed to have a more miniaturized structure, in response to demands for downsizing and high performance of the semiconductor devices. In order to manufacture more miniaturized and higher performance thin film transistors, it is necessary to form a thin insulating film such as a gate insulating film, in addition to conductive films for a gate electrode, source and drain wirings or the like. In general, an insulating film such as a gate insulating film of a thin film transistor is formed by a CVD method or the like (for example, Reference 1: Japanese Patent Laid-Open No. 2001-135824).